The human serum protein alpha1-Antitrypsin (AAT) is used for treatment of emphysema, but current production cannot satisfy the demand. Yeast- derived recombinant AAT injected into the rat was cleared from the serum too rapidly to have therapeutic benefit. The objective here is to test whether transgenic plants can be used to produce AAT or other proteins that have therapeutic benefits in humans. Once this is demonstrated, it will lead to a breakthrough in the production and use of AAT for treatment of emphysema and many other inflammation-related disorders. Malting of transgenic rice seeds will allow production of AAT in vast quantities and at low cost per unit. The specific aims in Phase I are to purify AAT protein from transgenic rice cell lines, to characterize the AAT protein structure and to test the clearing time of this AAT after injection into rats. The results of phase I will determine whether transgenic plant-derived AAT has the proper structure, thus providing a longer clearing time in rats and greater therapeutic potential than yeast-derived AAT. PROPOSED COMMERCIAL APPLICATION: Expression of human proteins in rice plant cells provided a low cost, high volume source of proteins that may have therapeutic value.